Here is the full list of all 50 Ultra Savage achievements.
Reach Level 180
Reach Level 160
Defeat Error
Defeat Oreb and Zeeb
Defeat Githeon The Galactic Conqueror
Enhanced Item +10
Do Ten Time Travels
Made A Costume
Reach Level 140
Do Six Time Travels
Defeat Xoreb
Defeat Nahash
Reach Level 100
Defeat King Bera the Reaper
Have Over 1'000'000 HP
Defeat Lord Pretty Face Coolinagi
Deal Over 10'000'000 Damage
Have Over 100,000 HP
Enhanced Item +6
Reach Level 80
Deal Over 1'000'000 Damage
Have Over 300% ATK SPD
Do Your Second Time Travel
Defeat Raki-Raki The Demolisher
Reach Level 60
Deal Over 100'000 Damage
Defeat Liki Lee The Amgi-Turner
Maxed Out A Skill
Have Over 100 CHI
Do Your First Time Travel
Deal Over 9'000 Damage
Have Over 50% CRIT
Defeat Heli Boss
Defeat Prince of Madness
Reach Level 30
Deal Over 1'00 Damage
Have Over 150% ATK SPD
Reach Fusion Level 10
Enhanced Item +3
First Enhancement
Equip a blade and meet Kairon
Reach Level 10
Have over 3'00 HP
Do your first fusion
Reach Level 200
Defeat Dr. Congo
Have Over 10'000'000 HP
Defeat Unlimited Error
Defeat Unlimited Nightmare Error
Enhanced Item +20